The TARDIS materialises on Spiridon, where the Doctor and Jo are aware a
Dalek plot is afoot. Teaming up with a band of Thals, the time travellers
soon discover an enormous army of Daleks is present on the planet. To make
matters worse, a Dalek scientific team is on the verge of gifting their
siblings with the invisibility powers of the Spiridon natives.

Production

In early 1972, producer Barry Letts and script editor Terrance Dicks
decided that part of Doctor Who's celebratory tenth season should
be an epic story rivalling in duration the longest serial to date,
the twelve-part The Daleks' Master Plan from
1965/66. Later realising that a single three-month serial would be
difficult for viewers to follow, they opted instead to devise two linked
six-part adventures. Each story would feature one of the Doctor's two
greatest foes: first the Master (in Frontier In
Space, written by Malcolm Hulke) and then the Daleks.

The Daleks had returned to Doctor Who after a lengthy absence in
Season Nine's Day Of The Daleks. The
serial's development had brought Letts and Dicks in touch with the
monsters' creator, Terry Nation. Nation had not written for Doctor
Who since The Daleks' Master Plan, and his
last contact with the show's production team had been in 1967 when he
refused permission for a story in which the Daleks appeared alongside the
Cybermen. In agreeing to allow the Daleks to return in Day Of The Daleks, however, Nation had obtained
from Letts and Dicks a first refusal on writing any future Dalek
stories.

Inquiries about a Dalek story coincided with a lull in
Terry Nation's workload, so he elected to tackle the scripts himself

As it happened, the production team's inquiries about a Dalek story for
Season Ten coincided with a lull in Nation's workload, and so he elected
to tackle the scripts himself. A storyline was commissioned under the
title Planet Of The Daleks on April 21st; by the time the six
scripts were requested on May 11th, the serial had been given the name
“Destination Daleks”.

One of the lead characters, Rebec, was christened after Nation's daughter
Rebecca. Another character, Petal, had his name reversed to Latep to
avoid confusion with Patel from Frontier In
Space. The planet was called Destinus before becoming Spiridon.
Nation was unsure how many Dalek casings would be available to the
production team: he originally envisioned both Rebec and Codal
masquerading as Daleks, for instance. Plans to kill off all the Thals at
the end of episode four were abandoned, partly to avoid the disapproval of
Ronnie Marsh, Head of Drama Serials. Also dropped were the individual
episode titles Nation employed (as he was unaware that their use had been
discontinued in Doctor Who in mid-1966). Latterly, the first
episode of “Destination Daleks” was heavily rewritten by Dicks
to bring it in line with the revised ending of Frontier In Space, with the Doctor injured and
unconscious.

Assigned to direct “Destination Daleks” was David Maloney,
another Doctor Who veteran whose last work on the programme had
been The War Games three and a half years
before. For the first time since 1964, four new Daleks were constructed to
join the three which had been retained from the Sixties. Maloney was
disappointed to discover that these were of generally inferior
workmanship, however, and so elected to keep them in the background as
much as possible. For the Dalek Supreme, Nation suggested using a
refurbished casing from the feature film Daleks: Invasion Earth 2150
AD which he had been given.

Just before location filming began, the title of the story -- allocated
the production code Serial SSS -- reverted to Planet Of The Daleks.
Only one site was visited, with Beachfields Quarry in Redhill, Surrey
posing as the ice pool on January 2nd and 3rd, 1973. Four days at the
Ealing Television Film Studios followed on the 4th, 5th, 8th and 9th,
concentrating on sequences in the chimney and the ice tunnels. Model shots
were captured on January 16th.

Katy Manning had her hair cut after location filming,
creating a continuity problem with the studio sequences

As usual, studio recording for Planet Of The Daleks took place on
fortnightly Mondays and Tuesdays, beginning on January 22nd and 23rd.
Unfortunately, Katy Manning had her hair cut shortly before these dates,
meaning that Jo's appearance in the filmed material is somewhat different
from the videotaped sequences. These first two days, which were allocated
to Television Centre Studio 4, saw the recording of most of episodes one
and two, as well as the Doctor and Jo's final scenes for part six.

More model filming occurred on January 27th and 29th. The second studio
block then took place on February 5th and 6th, this time in TC6. Most
scenes from episodes three and four were completed, as well as the Dalek
control room sequence for part two and the rocky area for part six.
The 8th was another model filming day, and the serial was completed on
February 19th and 20th in TC1. Although episodes five and six were the
main concern, several inserts for other installments were also recorded at
this time.

Sources

Doctor Who: The Handbook: The Third Doctor by David J Howe and
Stephen James Walker (1996), Virgin Publishing, ISBN 0 426 20486 7.